Extensible c-clamp



United States Patent EXTENSIBLE C-CLAMP Willard F. Leister, Lansdale, Pa. Application November 23, 1955, Serial No. 548,565 1 Claim. (Cl. 144-304) The present invention relates to clamps of the type commonly employed in various crafts for clamping two or more articles together, and is concerned primarily with a clamp that is adjustable so as to extend its usability over a wide range.

A clamp of the type with which thisinvention is concerned comprises a U-shaped frame having top and bottom legs that extend outwardly from a back. One of these legs takes the fixed jaw of the clamp, while the other leg is formed with a threaded opening which receives a threaded stem, the inner free end of which functions as the other jaw of the clamp. The work is clamped in between the fixed jaw and the end of the threaded stem.

It is evident that with the conventional clamps of the character above outlined there is a definite limitation on the size of the work which may be accommodated and which limitation is the distance between the free ends of the legs.

With the foregoing conditions in, mind, the present invention has in view as its foremost objective the provision of a clamp of the character indicated which is adjustable to vary the distance between the legs. With such an arrangement it is evident that the clamp may be adjusted to accommodate work of various sizes within a wide range.

More in detail, the invention has as an object the provision of a clamp of the type aforesaid which includes a back that connects the two legs, with the effective length of the back being adjustable. In carrying out this idea in. a practical embodiment, one leg such as the bottom is carried by a female back part which is formed with a channel. The other leg, which in this case would be the top leg, is carried by a back part which is a male element that is received in the channel of the female element aforesaid.

Another object is to provide in a clamp of the character indicated a back comprising complemental male and female elements, with one of these being formed with a series of recesses, any one of which is adapted to receive a detent carried by the other element. A snap fastener in the form of a spring is also included to maintain the detent assembled in any of the recesses. However, this spring may be overcome to withdraw the detent from one recess and cause its insertion in another.

Still another object of the invention is to provide in a clamp of the type noted a back comprising complemental male and female elements, one of which is provided with a roller which accommodates relative swinging movement between the two elements so that the detent may be withdrawn from any recess and the parts adjusted, after which the detent is moved into another recess.

Various other more detailed objects and advantages of the invention such as arise with carrying out the abovenoted ideas in a practical embodiment will in part become apparent and in part be hereinafter stated as the description of the invention proceeds.

The invention therefore comprises an adjustable clamp which consists essentially of a U -shaped structure made up of one leg that is carried by a female back element having a channel which receives a complemental back element that carries the other leg, with the two back elements being relatively pivotal and slidable, and one of them being formed with a series of recesses and the other with a detent adapted to be received in any of the recesses, together with a snap fastener in the form of a spring for maintaining the pin assembled in any recess in which it is received. One jaw of the clamp is carried by one of the legs, and the other jaw takes the form of a free end of a screw stem that is threaded in the other leg.

For a full and more complete understanding of the invention, reference may be had to the following description and accompanying drawing, wherein:

Figure l is a view in side elevation of an adjustable clamp made in accordance with the precepts of this invention, with an adjusted position being indicated by broken lines.

Figure 2 is a transverse horizontal section through the back, taken about on the planes represented by the lines 2-2 of Figure 1.

Figure 3 is another transverse horizontal section through the back, taken about on the plane represented by the line 3-3 of Figure l; and

Figure 4 is a detailed vertical section through the back, and is taken about on the plane represented by the line 4-4 of Figure 3.

Referring now to the drawing, wherein like reference characters denote corresponding parts, and first more particularly to Figure 1,

leg 11, with the two legs being connected by an adjustable back that is referred to in its entirety by the reference character B. The legs 10 and 11, together with the back B, define a U-shape, with the free ends of the legs spaced apart. The end of the leg 10 carries a fixed jaw 12. The end of the leg 11 is formed with a threaded bore (not illustrated), in which is screwed a screw stem 14. This stem 14 carries a ball 15 at its free end which is received in the socket 13 of a movable jaw 9. The other end of the screw stem 14 is provided with a head 16 which may have a knurled surface engagement, and may also be provided with appropriate wrench-engaging means such as the hexagonal socket shown at 17. It is evident that by rotating the stem 14, the distance between the fixed jaw 12 and the movable jaw 9 may be varied.

The top leg 11 is of a T cross section central web 18 and a crosshead 19. The male element of the back B is designated 20 and is also of a T-shaped cross section, as is clearly illustrated in Figures 2 and 3. This male back element 20 is integrally joined to the top leg 11 by a bend 21. Due to its T-shaped cross section, the male back element 20 also has central web 18 and a crosshead 19. As is clearly shown in Figures 3 and 4, the web 18 of the male back element 20 is formed with a series of recesses 22 which open inwardly; that is, towards the screw stem 14.

The bottom leg 10 is of a U-shaped cross section defined by side flanges 23, which are joined by a central portion 24. A female back element is designated 25 and is also of the same U-shaped cross section which identifies the bottom leg 10 to which it is integrally joined by a bend 8. The side flanges 23 of the female back element 25, together with the central portion 26 thereof, define a channel 27 in which is received the male back element 20.

The flanges 23 at the upper free end of the female back element 25 are formed with ears 28 that are formed with aligned openings 29. A roller 30 carries trunnions 31 which are journaled in these openings 29.

providing a the adjustable clamp of this invention is shown as comprising a bottom leg 10, and top as illustrated to facilitate hand,

This roller 30 bears against the crosshead 19 of the male back element 20. It is evident that this roller permits relative pivotal movement between the back elementsr2il and 25. and also permits of sliding movement between. the two.

The central. portion 26 of. the female back element 25. carries a detent in the form of a pin 32 having a.

pointed conical end 33 which facilitates insertion of the pin 32into any of the recesses 22. The pin 32 has. reducedv shank. 34 with a head 35, with the shank 34 andzhead 35 being received in a countersunk aperture in. the central part 26 of the female. back element 25.

A snap fastener in the form of. a spring is provided. This spring is referred. to in its entirety by the reference character 8'. It comprises a base 36 that is anchored to the inner face of the central portion 26 of the female back element 25. by the pin 32. Outstanding from the oppositeends of the base 36 to which they are integrally joined. are two arms 37 which. converge, with the converging ends being formed with beads 38.

The web 18 of the male back element 20 is formed with notches 39 on its opposite sides at each or" the recesses 22. Each pair. of these notches 39 is adapted to receive the beads 38 on the arms 37 of the spring S when the latter is brought into position opposite the notches.

Operation While the operation of the adjustable clamp of this invention is believed to be obvious from the illustration of the drawing and description of parts given, it may be briefly outlined as follows:

Assuming the clamp to be in the position of Figure 1 and that it is desired to extend the back B to provide a wider distance between the legs 10 and 11, the screw stem 14 is first unscrewed so as to separate the jaws 12 and 9 a sufiicient distance to permit the inner endsof the legs 10 and 11V to be moved towards one another'to provide pivotal action between the two elements 20 and 25 of the back at the roller 30. This pivotal movement will cause the pin 32 to be withdrawn from the recess 22 inwhich it is received. The back elements 20 and 25 may now be extended by simply causing the crosshead 19 of the male back element 20 to roll along theroller 30. This action is continued until the detent 32 is brought opposite to another recess 22. The legs 10 and 11 are then distended to cause a reverse pivotal action at the roller 30, which causes the pin 32 to enter the recess 22 opposite to which it has been positioned 4 by the adjustment, and the beads 38 on the arms 37 of the spring S will at the same time be positioned in the notches 39. Thus, the two elements of the back are securely held against longitudinal adjustment. The screw stem 14 is now operated in the usual way to vary the distance between the jaws 12 and 9 as required.

While a preferred specific embodiment of the invention is hereinbefore setforth, it is to be clearly understood that the invention is not to be limited to the exact constructions, mechanisms, and devices illustrated and described, because various modifications of these details may be provided in putting the invention into practice within the purview of the appended claim.

What is claimed is:

In a U-shaped clamp, an adjustable back comprising complemental male and female back elements, said female back element being of U-shaped cross section providing an outwardly opening channel, said male back element being received in said channel and of T-shaped cross-section providing a central web and an outwardly disposed crosshead, a roller journaled in said female back element and in engagement with the crosshead of said male back element, the central web of said male back element being formed with a series of inwardly opening recesses, a pin carried by said female back element and adapted to be received in any one of said recesses, a U-shaped snap spring normally maintaining said male and female back elements assembled, said spring having a base connected to said female back element and converging arms formed with inwardly extending beads engaging notches in the sides of the web of said male back element, legs outstanding from the opposite ends of said back elements, a fixed jaw carried by one of said legs, and a movable jaw carried byv the other of said legs.

References Cited in the file of this patent UNITED STATES PATENTS Switzerland Sept. 1, 1922 

